Aurororna

Aurororna, or the auroras, are natural light displays in Earth's polar regions. They occur in both hemispheres: the aurora borealis in the Arctic and the aurora australis in the Antarctic. The phenomenon is produced when charged particles emitted by the Sun travel through space and encounter Earth's magnetosphere. Guided by magnetic field lines toward high-latitude regions, electrons and protons collide with atoms and molecules in the upper atmosphere, exciting them and causing them to emit light.

Colors mainly come from excited oxygen and nitrogen. Green light, the most common, arises from oxygen at altitudes around 100–300 km. Red light comes from higher altitudes, while purples and blues result from molecular nitrogen at various levels. The display can appear as curtains, rays, or bands that seem to dance across the sky.

Auroras occur around the auroral ovals surrounding the magnetic poles and are intensified during geomagnetic storms when the solar wind is stronger. The intensity and extent depend on solar activity and the interplanetary magnetic conditions, often summarized by indices such as the Kp index. Higher activity expands the auroral oval and makes the displays more vivid.

Observation and reproduction: auroras are best viewed on clear, dark nights away from light pollution, typically in winter months at high latitudes. They can occasionally be seen at mid-latitudes during strong solar storms.

Cultural and scientific notes: auroras have been observed by many cultures throughout history and were scientifically explained and described in detail after advances in magnetospheric and atmospheric physics in the 18th century. Today they are studied as a magnetosphere–ionosphere interaction driven by solar activity.